1. Field of the Invention
The present invention relates to a paper feeder, wherein a paper sheet manually supplied from a paper supply opening is fed to a printing section by a roller, such as a platen roller, and is discharged also by the roller.
2. Description of the Related Art
In conventional paper feeders, in addition to a sensor for detecting whether a paper sheet is set at the paper supply opening, one or more sensors are provided in a paper conveyance path for detecting the state of the paper sheet remaining in the device or jamming of the paper sheet. For example, a device disclosed in Japanese Patent Unexamined Publication No. Hei. 2-141270 comprises a paper insertion set detecting sensor and a paper empty sensor for detecting the absence of a paper sheet provided in the paper supply opening and the paper conveyance path. Further, another device disclosed in Japanese Patent Unexamined Publication No. Hei. 8-290868 comprises a paper discharge sensor for detecting the state of a paper sheet remaining in the conveyance path.
Since a paper sheet may be left in the device or may cause jamming by an error during operation in the conventional paper feeders, the sensors are provided in the conveyance path for detecting these problems. That is, absence of a paper sheet remaining in the device can be confirmed at the time of supplementing new paper sheets.
However, in the conventional paper feeders, a sensor specially for detecting the state of a paper sheet remaining in the device is required. Therefore, in the case a paper sheet set at the paper supply opening needs to be detected, at least two sensors including a paper sensor and a sensor for detecting a remaining paper sheet are required so as to enable the cost reduction of the device.
Accordingly, an object of the invention is to provide a paper feeder capable of removing a paper sheet remaining in the device without the need of a sensor specially for detecting the remaining state of the paper sheet.
In order to achieve the above object, according to the invention, there is provided a paper feeder comprising: a roller for feeding a paper sheet supplied from a manual paper supply opening to a printing section and discharging the paper sheet after printing to a paper discharge opening; and controlling means for rotating the roller at a predetermined time before paper supply by a predetermined length toward the paper discharge opening.
The paper feeder has a configuration wherein a paper sheet supplied from the manual paper supply opening is fed to the printing section by the roller such as a platen roller, and is further discharged after printing to the paper discharge opening by the same roller. That is, a paper sheet is supplied and discharged only with one roller. Therefore, by rotating the roller by a certain length toward the paper discharge opening direction at a certain time such as when the power source is switched on, a paper sheet remaining in the device can surely be discharged to the paper discharge opening. For example, in the case the paper supply opening and the paper discharge opening are the same, the paper sheet supplied from the paper supply opening returns in the opposite direction after printing in the printing section. In this case, by inversely rotating the paper feed roller in the paper supply opening (paper discharge opening) direction by a certain length at a specific time such as when the power source is switched on, even in the case a paper sheet remains in the paper feeder, the paper sheet can be returned to the paper supply opening certainly. When new paper sheets are supplemented, the paper sheets can be set at the paper supply opening after removing the returned paper sheet manually.